Construction of buildings in areas with a steep relief of the terrain using the existing construction technique involves reforming of the terrain natural landscape because of the necessity of building artificial terraces by undercutting the slope soil with subsequent erection of special slope-holding structures in the form of relieving walls and similar constructions.
The foundation and the building frame made up of vertical and horizontal discs are erected on the thus prepared slope base.
The vertical force from loads of the building is resolved into sloping and normal components. Shear strain grows in the mass of the slope-base due to the sloping component of the load from the building being erected which is directed parallel to the slope generatrix. The relationship between the contour line and the vertical of the terrace depends upon the physico-mechanical characteristics of the slope soils.
Known in the art is the foundation of a building or structure erected on a rocky base; besides, in case of rocky beddings of the slope mass due account is taken of the bed's orientation relative to the dip of the relief. Given non-rock soils of the slope, the slope gradient is most often decreased with the aim of ensuring the stability of the slope-building system, which is associated with a greater volume of earth-moving operations.
The foregoing specifics of the development of slopes complicate the application of industrial methods of building operations.
As was noted above, the greater part of the areas with a steep relief of terrain is located in seismic-prone zones, where the utilization of rational structures of terrace or terrace-cascade type of buildings is limited or ruled out because of unsatisfactory dynamic characteristics of the building structures and eventually low operational reliability of the existing buildings, structures under seismic effects. The stiffness of buildings is usually increased by introducing special vertical structures in the frame which are shaped as diaphragms, bracings and stiffness cores and normally saturated with costly reinforcing steel.
USSR Inventor's Certificate No. 553334, IPC E 02 D 27/34 teaches the construction of the foundation of a cascade-type building or structure erected on the slopes of rocky massifs in seismic-prone zones.
The slope is prepared for the foundation in a broken line by virtue of ascending, horizontal and descending undercuts of the slope.
The foundation is made in the form of a reinforced concrete slab copying the shape of an undercut slope. In order to ensure stability to seismic effects, the foundation is provided with vertical longitudinal and transverse ribs, with bearing shoes being mounted under the supporting constructions of the prefabricated reinforced concrete frame of the building and arranged in the place of intersection of these ribs. The building frame contains vertical and horizontal thin, elongated structural components.
Disadvantages of the aforementioned solution are the undercutting of the slope base down to bedrocks, development of the base soil of a complex broken configuration, high labour intensity and costs of the foundation erection and low reliability during seismic effects which does not rule out the slipping down of the entire massif, particularly if the beds are parallel to the slope.
Besides, the application of this solution is confined mostly to the slopes of rocky massifs due to the transition of substantial shear stress from the sloping component of the building load to the slope. In areas with steep slopes and extremely rolling terrain, namely, slopes with the soils having low physico-mechanical properties (the angle of internal friction, adhesion or bond, consistency, stress-strain modulus) ravines, hills, dumping ground, it is impossible to use this technique because of an insufficient bearing capacity of soils in the slopes, particularly in seismic-prone zones.
It is a specific object of the invention to construct a building or structure erected on slopes whose design would make it possible to rule out the impact of the sloping component of external loads of the frame and foundation on the slope soil.